Diffusion at anodically bonded interfaces

The diffusion of gas molecules into cavities closed by anodic bonding is quantified by the annealing of specially designed test structures. Annealing is performed at temperatures in the range 150-430 deg C for several days. An increased concentration of molecules within the closed cavities after heat treatments is verified both electrically and optically. The diffusion of gas into the cavities is found to be substantial at temperatures above 300 deg C. A diffusion parameter, the diffusion coefficient times the height of the bonded interface, is found from curve fitting of experimental data with an analytic expression for diffusion.